1. Challenge: Low frequency foreground – hot, confused sky HI 21cm signal ~ 10 mK Foreground: T ~ 100  z)^-2.6 K Highly ‘confused’: 1 source/deg^2 with S 140 > 1 Jy Synch. smooth ~ 100MHz vs. 21cm lines ~ 1 MHz 0.5 to 5.0 GHz

2. Chromatic aberration: Frequency differencing with MHz channels doesn’t work well due to frequency dependent far-out sidelobes 142, 174 MHz

4. 6C source counts > 1Jy (S max = 200 Jy) Simulation: effects of residual calibration errors

5. UVSUB ~ ‘real-time’ source removal IMLIN ~ post-processing freq fitting (3 rd order)

6. Datta+ 09 0.1%1% For errors constant over 1 day: DNR requirement ~ 0.2% calibration errors

7. 300 hours 0.1% calibration errors Datta + Bowman in prep UVSUB IMLIN

8. Focus: Reionization (power spec,CSS,abs) Very wide field: single dipole + screen Correlator: FPGA-based from Berkeley wireless lab Staged engineering: maintain GB test installation  PWA  PSA J. Aguirre, D. Jacobs (Penn), C. Carilli (NRAO)

9. PAPER: Staged Engineering Broad band sleeve dipole + flaps FPGA-based ‘pocket correlator’ from Berkeley wireless lab S/W Imaging, calibration, PS analysis: AIPY + Miriad/AIPS => Python + CASA, including ionospheric ‘peeling’ calibration 100MHz200MHz BEE2: 5 FPGAs, 500 Gops/s Beam response

10. Western Australian deployment in 2008

11. CygA 1e4Jy PAPER/WA -- 4 Ant, July 2007 RMS ~ 1Jy; DNR ~ 1e4 Parsons et al. 2009 120MHz180MHz

12. Paper – South Africa Karoo site 16 elements by Nov 1, 2009 32 elements possible by Jan 1

13. PGB 16 dipole, 3x24hr scale -10 to 10 Jy rms ~ 100 mJy FWHM ~ 20 ’